Take note of Mary-Kate Olsen
's bold brows. "Thick brows make your face look more youthful and can frame your eyes better," says Crooks. Thicker arches work best on natural brows, so let all hairs grow in for three to four weeks before having a pro shape them. To fake fuller brows in the meantime, dip an angled brush into a matte shadow in a matching shade, or use a pencil to fill in large gaps. "Be sure to apply in short, light strokes, and follow your current shape for the most natural look," suggests Kiehl's grooming expert Soul Lee.